Arch Linux

rafauke

Member

Registered: 2022-02-07

Posts: 3

NVIDIA Prime issue: external displays refresh rate & sync

Hello,

I am struggling a bit with figuring out if I can get the second external display to work correctly and would like to ask if you have some ideas. This is an NVIDIA Prime Laptop setting. Some basic info:

Kernel: 6.9.8-arch1-1
DE: Plasma 6.1.2
WM: kwin
CPU: Intel i7-10870H (16) @ 5.000GHz
GPU: NVIDIA GeForce RTX 3060 Mobile / Max-Q
GPU: Intel CometLake-H GT2 [UHD Graphics]
nvidia-dkms: 555.58.02-1

Wayland-related modules installed and their versions:

pacman -Q | grep wayland
egl-wayland 2:1.1.13-2
kwayland 6.1.2-1
kwayland5 5.116.0-1
lib32-wayland 1.22.0-1
qt5-wayland 5.15.14+kde+r58-1
qt6-wayland 6.7.2-1
wayland 1.23.0-1
wayland-protocols 1.36-1
wayland-utils 1.2.0-1
xorg-xwayland 24.1.0-1
xwaylandvideobridge 0.4.0-2

The connected displays:

interface: 'wl_output',                                  version:  4, name: 64
        name: DP-2
        description: LG Electronics LG ULTRAGEAR/104NTPC5Z856
        x: 2560, y: 0, scale: 1,
        physical_width: 597 mm, physical_height: 336 mm,
        make: 'LG Electronics', model: 'LG ULTRAGEAR/104NTPC5Z856',
        subpixel_orientation: unknown, output_transform: normal,
        mode:
                width: 2560 px, height: 1440 px, refresh: 143.973 Hz,
                flags: current
interface: 'wl_output',                                  version:  4, name: 66
        name: eDP-1
        description: Najing CEC Panda FPD Technology CO. ltd eDP-1-0x004B
        x: 1556, y: 1440, scale: 1,
        physical_width: 344 mm, physical_height: 194 mm,
        make: 'Najing CEC Panda FPD Technology CO. ltd', model: 'eDP-1-0x004B',
        subpixel_orientation: unknown, output_transform: normal,
        mode:
                width: 1920 px, height: 1080 px, refresh: 144.014 Hz,
                flags: current
interface: 'org_kde_kwin_blur_manager',                  version:  1, name: 67
interface: 'org_kde_kwin_contrast_manager',              version:  2, name: 68
interface: 'org_kde_kwin_slide_manager',                 version:  1, name: 69
interface: 'wp_drm_lease_device_v1',                     version:  1, name: 75
        path: /dev/dri/card0
interface: 'kde_output_device_v2',                       version:  8, name: 76
interface: 'wl_output',                                  version:  4, name: 77
        name: DP-1
        description: Dell Inc. DELL U2717D/J0XYN716679S
        x: 0, y: 0, scale: 1,
        physical_width: 597 mm, physical_height: 336 mm,
        make: 'Dell Inc.', model: 'DELL U2717D/J0XYN716679S',
        subpixel_orientation: unknown, output_transform: normal,
        mode:
                width: 2560 px, height: 1440 px, refresh: 59.951 Hz,
                flags: current

*The problem:*

I have three video outputs in my laptop: HDMI & USB-C on the back, mini DP on the right.

The problem is that while my built-in laptop display and the LG (which is connected through mDP on the right) work flawlessly at 144hz, the second external display, 27" Dell (which is connected through USB-C on the back) should work in 60hz, but it works somewhere in ballpark of 18–40 fps. VSync tests in browser when run on that display give ~18-22fps.

My understanding is that LG is connected through mDP directly to NVIDIA and because of that works fine, but Dell is connected through USB-C on the back of the laptop, and it's going through integrated graphics.

Is there anything I can do to have that second external display work as it should? ~20 fps is kind of hard to work with

I would be grateful for any suggestions

Last edited by rafauke (2024-07-09 15:33:50)

V1del

Forum Moderator

Registered: 2012-10-16

Posts: 25,223

Re: NVIDIA Prime issue: external displays refresh rate & sync

Wayland efforts in this space are quite new and potentially not fully fleshed out yet. What's the situation on xorg?

FWIW Wayland NVIDIA anything requires enabled modesetting, is that the case?  https://wiki.archlinux.org/title/NVIDIA … de_setting

rafauke

Member

Registered: 2022-02-07

Posts: 3

Re: NVIDIA Prime issue: external displays refresh rate & sync

Wayland efforts in this space are quite new and potentially not fully fleshed out yet. What's the situation on xorg?

FWIW Wayland NVIDIA anything requires enabled modesetting, is that the case?  https://wiki.archlinux.org/title/NVIDIA … de_setting

Yes, the modesetting is set. In general, it works okay if I connect through mDP, but the other two outputs struggle.

In another setup, where I have an external 15.6 tabletop display with 144hz, when it's connected through USB-C on the back it outputs somewhere around 31 fps in vsync tests. I have checked with Plasma+X11 and Gnome+X11 but unfortunately the behavior is the same (no visible impact on performance/refresh rate of the external display).